Radio telegraphy and telephony receiver.



G. W. PICKARD.

RADIO TELEGRAPHY AND TELEPHONY RECEIVER.

APPLICATION FILED APR. 17. 1914. RENEWED MAR. 13. 1911.

1,224,499., Patented Ma l, 1917.

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vG. W. PICKARD.

RADIO TELEGRAPHY AND TELEPHONY RECEIVER.

APPLICATION FILED APR. 17, 1914. RENEWED 1111111. 13.1911.

LQQEAQQQ Patented May1,1917.

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1 5 X51 ,Bf 6 Em IWWMWW WWWHME [WW 1 J .K 6 6 W 1 DWWDHHHW )WHWWHHHW 1EHWWWW) MWWWMW 6 5 Inventor: 'feka hzLi'htr Pick 63 GREENLEAF WHITTIERPICKARD, 0F AMESBURY, MASSACHUSETTS, ASSIGNOR TO WIRELESS SPECIALTYAPPARATUS COMPANY, OF BOSTON, MASSACHUSETTS, A.

CORPORATION OF NEW YORK.

RADIO TELEGRAPHY AND TELEPHONY RECEIVER.

Application filed April 17, 1914, Serial No. 832,591. Renewed March 13,1917, Serial No. 154,560.

to be the best of the various forms in which.

the principles of the bodied.

This invention relates to improvements in receiving apparatus for radiotelegraphy and telephony, and consists of the apparatus and arrangementsthereof disclosed herein, the object of the invention being to providesimplified and more efiicient'apparatus.

Of the drawings, which are largely diagrammatic, Figure 1 shows anarrangement wherein the second coil C has only one side invention may beem connected to the receiving apparatus D, T,

which may be grounded, as shown; Fig. 2 shows a like arrangement, savethat the coupling between antenna A and coil B is made inductively, byway of coil B instead of directly'and conductively as in Fig. 1; Fig.

Fig. l chiefly in the inductive coupling rep-' 3 shows an arrangementsimilar to that of Fig. 1, save that instead .of one coil B as in Fig.1,two coils B and B are employed, so wound and connected that theircorresponding ends are of opposite polarity, as indicated by the signsat their left ends; Fig. t shows an arrangement similar to Figs. 3 and1, save that the coupling between. antenna A and coils B and B is madeinductively, by way of coils B and B as in the case of B Fig. 2; Figs. 5and 6 show modifications of the arrangement of Fig. 3, that of Fig. 5being a direct or conductive antenna coupling and that of Fig. 6 beingan inductive coupling by way of coil B and Fig. 7 is a modificationinvolving the combination of an adjustable conducting bridge Econnecting coils B and B In each of the figures, A represents anyordinary or suitable antenna or aerial, G a. ound connection or asuitable substitute or equivalent thereof, '1 a suitable indicator as anordinary electromagnetic telephone re- Specification of Letters Patent.

eon

Patented May 1, 19317..

ceiver, and D a suitable detector, as one of the crystal rectifier orgas rectifier types. Also K represents any suitable electricalcondenser, the arrow indicating adjustability of the capacity thereof.In all the figures, the .double arrows indicate variability of couplingbetween the coils shown adjacent to such arrows; and the single arrowsat the ends of leads indicate adjustability of the 'inductances at whichthe arrows are directed.

In Fig. 1. coil B is a coil of suflicient length to cause its naturalperiod to be equal to the shortest desired wave-length. As shown, only asmall portion of this coil is included in the connection A G, and thisis variable as. shown, to permit adjustment of said connection AG totheperiodicity of the waves from the distant. transmitter. .The coil Cis adapted to slide inside'coil B as shown (or outside), and consists ofonly a few turns of coarse or flat wire, its natural period being muchsmaller than the shortest desired wave-length. lhe variation of couplingbetween coils B and G causes a variation of the natural period of theleft hand part of coil B which is not included in the connection A-G. V

The arrangement of Fig. 2 difiers from resented as-by Way of coil B Inthis'case, however, the tuning of the connection A-Gr to the waves isefl'ected by the operation of adjustable condenser K. 7 The arrangementof Fig. 3, comprises, in addition to the parts described above, twocoils C,'C -instead of the single coil C of Fig. 1, each of the paircooperating with its corresponding coil B, B the detector D beingconnected between the left hand ends of coils C, C. By the couplingadjustments indicated by the double arrows,,the natural period of thesystem B,-B C, C may be made to correspond to any desired wavelength. Anadjustable connection A is provided for the second coil B, so that it,

as well as coil B, may be varied as to their above stated, the two coilsB, B have their right hand ends connected by a lead A the coils B and B1 providing the inductive coupling with coils B and B As in the otherfigures, the left hand ends of coil B,

, the inductive coupling is employed.

obyway of condensers K and K respectively.

B are open circuited, as are the right hand ends, adjacent to them, ofthe coils C, C.

In Fig. 5, the long coil B, B has a few turns at or about the centerconnected, by

way of the variable connections, in the connection AG. Observe thepositive and negative signs. in Figs. 3 and 4 were placed back to back,in respect of their right hand ends. Coils C, C are arranged, as inFigs. 3 and 4, one" adjacent to a positive end of the long coil, and theother adjacent to the negative end. The arrangement of Fig. 6 is likethat of Fig. 5, save that the inductive coupling is employed, by way ,ofcoil-B as in Fig. 4, and the connection AG is tuned by variablecondenser K as i n'FigsQ and 4 where In the-arrangement of Fig. 7 thelong coils B B are connected to antenna coil.

B in any suitable way, as electrostatically Coils C, C and intermediatesD, 'I are arranged, as before, at the free or open ends of coils B, Brespectively. 'The proper adjustments are obtained here not only byvarying the coupling between C, C and B B but by the movement to leftorright of the conductin bridgeindicated at E which connects coils 1 and Bto form a potential node. j

The arrangements ofFigs. 2-7 inclusive embody all desired or necessaryfeatures of the arrangement of Fig. 1 as described and shown. K

This is as if coils B, B

and the coils being bodily. movable with reference to one another; thesecond coilv having unilaterally connected to it suitable means forindicating the received intelligence, substantially as and for thepurpose described.

2. In' a radio receiving system, the combination with two coils, ofsufiicient length to "permit the natural period thereof to besubstantially equal to the shortest desired wave length, of a secondpair of coils, consisting of a few turns and having a natural periodmuch smaller'than the shortest desired wave-length, each pair of coilsbeing open-circuited, and the first pair of coils being so wound andconnected that their free ends are of opposite polarity; the second pairof coils being arranged in cooperative relation with the first pair andbeing movable relative thereto and having unilaterally connected to themsuitable means for indicating the received intelligence, substantiallyas and for the purpose described.

@ GREEN LEAF WHITTIER PICKARD.

In presence'of .M. C. HANNoN, W. J. BARKLEY.

